<!DOCTYPE html>
<html>
<head>
  <style>
    .shouldComposite {
      width: 30px;
      height: 30px;
      margin: 4px;
      background-color: green;
    }

    .shouldNotComposite {
      width: 30px;
      height: 30px;
      margin: 4px;
      background-color: red;
    }

    .positioned {
      position: relative;
    }

    #willChangeAuto {
      will-change: auto;
    }

    #willChangeOpacity {
      will-change: opacity;
    }

    #willChangeTransform {
      will-change: -webkit-transform;
    }

    #willChangeLeft {
      will-change: left;
    }

    #willChangeRight {
      will-change: right;
    }

    #willChangeTop {
      will-change: top;
    }

    #willChangeBottom {
      will-change: bottom;
    }

    #willChangeFilter {
      will-change: -webkit-filter;
    }

    #willChangeBackdropFilter {
      will-change: backdrop-filter;
    }

    #willChangeCombinationThatComposites {
      will-change: transition, -webkit-animation, opacity, z-index;
    }

    #willChangeZIndex {
      will-change: z-index;
    }
  </style>

  <script>
    window.addEventListener('load', function() {
      if (window.testRunner) {
        document.getElementById("layertree").innerText = internals.layerTreeAsText(document);
        testRunner.dumpAsText();
      }
    }, false);
  </script>
</head>
<body>
  <div id="willChangeAuto" class="shouldNotComposite"></div>
  <div id="willChangeOpacity" class="shouldComposite"></div>
  <div id="willChangeTransform" class="shouldComposite"></div>
  <div id="willChangeLeft" class="shouldNotComposite"></div>
  <div id="willChangeLeft" class="positioned shouldComposite"></div>
  <div id="willChangeRight" class="shouldNotComposite"></div>
  <div id="willChangeRight" class="positioned shouldComposite"></div>
  <div id="willChangeTop" class="shouldNotComposite"></div>
  <div id="willChangeTop" class="positioned shouldComposite"></div>
  <div id="willChangeBottom" class="shouldNotComposite"></div>
  <div id="willChangeBottom" class="positioned shouldComposite"></div>
  <div id="willChangeFilter" class="shouldComposite"></div>
  <div id="willChangeBackdropFilter" class="shouldComposite"></div>
  <div id="willChangeCombinationThatComposites" class="shouldComposite"></div>
  <div id="willChangeZIndex" class="shouldNotComposite"></div>

  <pre id="layertree"></pre>
</body>
</html>
